PROJECT SUMMARY/ABSTRACT Cardiovascular disease (CVD) afflicts nearly 50% of all African-American (AA) adults, and they are 30% more likely to die from CVD than the overall US population. Compared to non-Hispanic whites, AAs are 82% less likely to meet the ideal levels for 5 or more of the cardiovascular (CV) health components that comprise the American Heart Association (AHA) Life's Simple 7 (LS7). LS7 is an evidenced-based metric of 7 health- promoting behaviors and biological risk factors that improves CV outcomes: physical activity, diet, smoking, body mass index, blood pressure, total cholesterol, and glucose. AAs have poorer health status than whites in every LS7 component except total cholesterol. Mobile health (mHealth) lifestyle interventions through digital communication and devices are promising ways to improve CV health and outcomes among AAs; however, there is a paucity of effective, culturally relevant, evidenced-based interventions available. The major goal of our project is to apply a community-based participatory research approach to rigorously refine and test the feasibility and preliminary efficacy of our existing CV health/wellness digital application (app) prototype to improve CV health among AAs. The refined app will focus on promoting the LS7 framework with incorporation of user-individualized and interpersonal features. We hypothesize that our behavioral theory-informed, app- based, intervention will be feasible and improve CV health among AAs in faith communities from baseline to 6- months post-intervention. This R21 proposal aligns with the NIMHD's focus on ?impacting the health determinants that contribute to poor health outcomes and to health disparity conditions?. Building on our longstanding partnership with local AA churches and preliminary work, we propose two aims. Aim 1 will refine our app to promote LS7 with inclusion of user-individualized and interpersonal features. We will use a formative research process and qualitative methods to refine the app within a focus group series with 15 AA adult community members. Primary outcomes are app usability and user satisfaction. Aim 2 will assess the feasibility and preliminary efficacy of the refined app for promoting LS7 among AA adults in faith communities by conducting a cluster randomized controlled trial of 200 AA adults. Primary outcomes are change in LS7 score from baseline to 6-months post- intervention and app engagement/usability. Secondary outcomes include the following psychosocial measures: self-efficacy, self-regulation, social support, religiosity/spirituality, optimism and perceived stress. An established community steering committee will provide input for all activities. Our project is innovative as our mHealth lifestyle intervention integrates behavioral theory-informed and empirically-supported components to influence LS7 among AAs. If successful, our results can pave the way for use of evidence-based mHealth tools to increase prevalence of ideal CV health among AAs and other underserved populations.